PIE currently adds full or partial support to IE 6 through 8 for the following CSS3 features

PIE stands for Progressive Internet Explorer. It is an IE attached behavior which, when applied to an element, allows IE to recognize and display a number of CSS3 properties. Consider, if you will, the following CSS:

PIE currently adds full or partial support to IE 6 through 8 for the following CSS3 features

• border-radius
• box-shadow
• border-image
• multiple background images
• linear-gradient as background image

http://css3pie.com/about/

PIE currently adds full or partial support to IE 6 through 8 for the following CSS3 features

原文：http://www.cnblogs.com/zyip/p/4489302.html